Brian S

I'll try to keep this sort and sweet...

In early '05 I upgraded rims to 18" ASA ST3's with Dunlop Direzzas. Car vibrated horribly. Two Roadforce balances did not help. I lived with the issue until it was time to replace the tires.

Fast forward to a couple months ago. I did a lot of research on tires and settled on the ContiExtremeContacts. They were mounted and vibrated around 75 and above, but were smooth below that. Had them balanced again and shop noted two tires had significant runout and one rim appeared to be very slightly bent, but they didn't think that was an issue. It was smoother after the second balance, but it still vibrated a little, so I decided to send those tire back and ordered ContiProContact in hopes they would be a little more civil since they are a "touring" tire.

After mounting the ContiProContacts, it still vibrated, and a little worse. I took it back, and thats when the shop owner asked if hub rings were installed (rims are not hubcentric). Nope, a shop must of lost them a long time ago because I forgot the rims cam with them. I ordered a set of aluminum hubcentric rings, installed, and car still vibrated. They balanced the tires again, but it still vibrated at 75 and above.

I have winter tires on the stock LS400 rims, so they balanced and installed them. Car rode smooth as glass. They proceed to try winter tires on front, summer on back, and vice versa. None of that results in the vibration going away.

The shop does not have a roadforce (they use some snap-on model), but they take the car to a local tire shop that had a road force machine. Three wheels need weights, and one wheel supposedly is right on balance.

Car still vibrates. I, as owner, am frustrated beyond belief. The shop has spent a ton of time on my car trying to rid this vibration, but nothing is working. The shop is happy to look into it further, but we don't want to go on wild goose chase, so we need to know what might be worth considering. So I turn to you learned folks for some advice and suggestions.

Here are worthy notes:
(so much for short and sweet)I am at a loss. I could not express my appreciation in words if someone could help pinpoint and solve this once and for all.

Thank you,

Brian

DaveGS4

iTrader: (2)

Brian, I assume this issue happens in both dry and wet conditions? Just trying to eliminate one potential cause (water in wheel interior).

Have you had the car on a lift and examined the interior of the wheels for any bends? I guess though if they've done this since day one that's probably not the issue.

I have the OEM 18s with I think the same tire size and while I don't have it lowered any longer, have never had that problem at any speed with either my prior Pirellis or the Conti's I have now.

Brian S

Thanks Dave for your response. I was thinking of you when I decided to go with the ContiProContact. I was hopeful they would be more civil.

It happens wet or dry. Last year, the owner of a performance shop trying to fix my Dunlop vibration last year mentioned that water in the rim during rain will sometimes cause vibration. I wish that was the only time it vibrated..

Concerning a bent rim, recently when this shop was balancing the ContiExtremeContacts on their snap-on machine, he noted it appeared one rim was very slightly bent. But the owner expected if it was case, the suspension should be able to absorb it. If it was that rim, I would have expected it to go away when they where swapping the front, and then back, with the winter rims. And if it was a bent rim, wouldn't it happen from second one after getting on the highway?

The shop I have service performed now does not do much volume in tire service. That is partly why they were more than willing to try a roadforce after exhausting everything else.

What really gets me is why sometimes it take a minute or so for the vibration to start. It's so weird. I really wish this could be linked to something specific.

Brian

DaveGS4

iTrader: (2)

The Conti's ride much better than the Pirelli's did, suspect mainly due to a much larger sidewall. But its a difference in ride quality, not vibration.

I've had the water issue with my HREs on my GS during heavy rain. I don't drive it in the rain all that much so it doesn't cause much of a problem.

When I had the 18" Piaa wheels on my GS (they were 1 piece and bent fairly easily) it had similar vibrations at certain speeds so that may be part of your problem. Did your wheels do it when you gt them brand new (with no possible bends) or did it sneak up on you over time?

tech169

I would have all the tires roadforced balanced with the proper fittings.Most aftermarket places balances the tires just using cones on the inside and outside of the wheel.I would rec. using a cone on the inside of the wheel and "fingers" on the outside of the wheel when balancing.Most dealerships have these fingers
(Lexus service tool)and have a roadforce machine.A roadforce machine will let you know if your rim is bent too much or the tire is the problem.Alse if your tires have fix a flat in them they will never balance.I worked on an sc430 with the same problem.After using the fingers to balance,it corrected the problem.Note:the thinner the side wall of the tire,the easier it is to bend a wheel.

Brian S

The tires are brand-new, and as noted in my post, after two or three unsuccessful balances on a regular machine, they took them to another tire shop to have them roadforced.

Have you all ever heard of the vibration coming after a minute or so? It like the tires or something warm up and it starts vibrating and doesn't stop. Below 70, when properly balanced, they are perfectly smooth. Ever heard of cheap bolts not properly hold the rims??

Thanks,

Brian

tech169

If they were roadforced,then what did the tires roadforce at?

Brian S

I don't know, and I am wondering. My shop took it to the tire place. I may call on Monday to see if they have the numbers. I could talk to the actual tire place, but I don't want to bug them too much, as they probably did the roadforce as a favor to my shop.

One tire has no weight. The others have a weight covered with duct tape and possibly another weight stuck in another area.

Brian